Earlier quoted context omitted.
Would Oregon necessarily be against this? This seems like a great way to (a) get rid of nut jobs from the state legislature, and (b) get rid of a bunch of counties that sinkholes (financially speaking).
Honestly I see this failing in Oregon not because anyone is particularly against it, but because the Republicans in the state legislature have no power and the issue would never be brought to the floor.
But for the sake of argument, say they somehow can. What then? Would they actually go through with it?
I suppose it goes to their own personal careers. Would they have a better chance of personal success in the new Idaho legislatures or in the current Oregon one?
Seeing that the population of Oregon is 4.2M and the new Idaho would be relatively unchanged at 1.7M (these counties combine to 0.06M people), I'd suppose they would want to stay with Oregon as the prestige and career flexibility would be greater in a more populous and richer state. Whatever the new districts of new Idaho would be, these new-comers would still be a small fraction of the legislature.
The only way I can see that they would have better careers in new Idaho would be in national politics. And then they have to fight amongst each other and the old Idaho politicians, all of whom would be jealous at the attention these new-comers would have. Unless one of them is especially gifted/lucky, I'm not seeing that as a high likelihood.